(1) Field of the Invention
The invention relates to propellant combustion. More particularly, the invention relates to combustion of monopropellants.
(2) Description of the Related Art
Use of monopropellants is known in rocket propulsion and auxiliary/emergency power generation. U.S. Pat. No. 5,485,722 identifies the catalytic decomposition/combustion of hydroxylammonium nitrate (HAN)-based monopropellants. In general most HAN-based propellants are mixtures of three primary components: HAN, water, and a fuel. For miscibility the fuel is typically ionic, partly ionic, or polar. The fuel may be an ionic salt like HAN. Triethanol ammonium nitrate (TEAN) and 2-hydroxyethyl-hydrazine nitrate (HEHN) are two of the most common organic types. Partly ionic fuels may include amino acids (e.g., glycine). Polar fuels may include alcohols (e.g., ethanol or methanol). Most of these propellant mixtures are roughly 60%-80% HAN. HAN concentrations may be reduced by addition of more water. This has been used to lower combustion temperatures to levels survivable by materials involved in traditional monopropellant thrusters. Some of the more exotic mixtures use small amounts of ammonium nitrate as a further oxidant and/or mix multiple fuels into the blend.